Tweaking an 87 Olds 307 - opinions?

[skryla]

Would 72 350 heads bolt up to the 307 block?

 

[MrLightning]

Would 72 350 heads bolt up to the 307 block?

simply put- scrap the idea that doing much of anything to a 305/307 will accomplish an overall increase of HP or torque, needed to justify the investment. These motors served their purpose ( what purpose that is, ive never heard said). The money youll eventually spend on parts for these boat anchor-motors would be better spent on legit performance upgrades on a olds 350 needing rebuilt or upgrading a good condition olds 350.

 

[skryla]

Here are your issues, tiny port heads that flow 130/105 cfm stock, small roller can with piddly lift, less than 8 to 1 compression, awful factory exhaust and very aggressive timing. If your stuck on stock heads and block, they need much help. You will need custom pistons or a lot milling and max porting. Find a 72 350 with 7a heads and paint it black and build it how you want.

Why specifically a 72 engine? I just happen to have on in the shed.

 

[MrLightning]

Here are your issues, tiny port heads that flow 130/105 cfm stock, small roller can with piddly lift, less than 8 to 1 compression, awful factory exhaust and very aggressive timing. If your stuck on stock heads and block, they need much help. You will need custom pistons or a lot milling and max porting. Find a 72 350 with 7a heads and paint it black and build it how you want.

Why specifically a 72 engine? I just happen to have on in the shed.

too be honest with you, find a 69 olds 350....were it not for the rarity and price, otherwise 70-72 are all good!

 

[olds307 and 403]

To fool people with the 7a heads. Good chance any 40+ year old engines will need rebuilt. If in good running shape, pick up a small cam, vin 9, smog 455 or custom,, put in a timing set and gaskets and drop it in.

 

[QS442]

Has anyone put #5-8 heads on a 307 and aluminum intake and felt any significant difference?

 

[83hurstguy]

I was going to put 330 heads on mine, but ended up sticking with the 5A's (3317's). 307 heads get a terrible rap, but the 5A's aren't horrid... the short turn isn't as bad as some others due to the smaller port. The exhaust side is pinched over the short turn, but some porting can fix that. The divider issue is a concern with any late head. A lack of cam and compression hurt the motor way worse.

The Stock guys do very well with unported 3317 heads and A4 intake manifolds. (super stock is heavily ported, but they still work well). I used to have pics hosted with silicone molds of the ports, but lost that space a year or two ago.

I think you'll have issues getting the 350 heads to work (bore size difference), but that's postulation.

I'm not arguing that a 350 isn't a better investment for money spent, just saying that internet conjecture and group think isn't always true.

 

[skryla]

I have a rebuilt 72 350 with 3000 miles and 7a heads in the shed. I also have a set of 69 #5 heads with 2" valves that need to be redone. I did not do the rebuilt on the engine. It was done by the previous owner before I yanked it from my 72 442. I drove it about 2000 miles before I pulled it with no issues. It ran surprisingly strong.

What I'm getting from this thread is that I have a build and swap in my future? Any ideas to keep the build under $3,000 and get the most from my money? Do I keep the computer?

Any and all ideas and (constructive) comments are welcome.

 

[DoubleV]

Well what are your goals with the 307?

 

[skryla]

Well what are your goals with the 307?

I want to wake it up - definition - 250 to 300hp 300-350tq